While progress is now made toward microelectronic devices of higher integration density, multi-pin thin-layer packages are used. For the manufacture of multi-pin structures, the technology for forming bump electrodes with a height of 10 to 100 μm or more as the connecting terminal is necessary. When electrodes are formed by electroplating, a chemically amplified positive photoresist composition is often used because a high sensitivity and high resolution are rather readily achievable and stripping of a photoresist film after plating is easy.
When a resist pattern is formed on a copper substrate, however, many resist materials give rise to the so-called footing phenomenon that a thin resist layer is left at the interface with the substrate. For example, Patent Document 1 discloses the addition of a benzotriazole compound to a resist material, which forms a pattern of improved profile on the Cu substrate. Patent Document 2 describes that a polymer comprising recurring units of polyacrylate is incorporated in order to improve the solubility of a thick film. Additionally, the developing time is shortened. These compositions, however, are liquid compositions which are often applied onto supports by spin coating. Under certain coating conditions, floating matter known as cotton candy generates to contaminate the surrounding of the system. When the support has steps on its surface, bubbles known as voids form.
Only a few reports including Patent Document 3 refer to chemically amplified positive resist film laminates. There is the problem that when the resist film is transferred to another support, voids form as in the case of liquid resist compositions if the support has steps. There is the demand for a chemically amplified positive resist film laminate which eliminates the void problem when the resist film is transferred to a stepped support.